Conventional tool changers are limited both in their capacity and speed of operation. This restricts their applicability and increases the cost of operation of the machine tool with which the tool changer is associated. The performance of conventional tool changers is far from adequate for a certain high speed drilling and routing machine used in the manufacture of printed circuit boards. This machine has a positioning mechanism of the type disclosed in patent application Ser. No. 740,151, filed Aug. 5, 1991, for ARRANGEMENT FOR PROVIDING PLANAR MOVEMENT OF A MACHINE TOOL, and a spindle as set forth in patent application Ser. No. 660,149, filed Feb. 22, 1991, for ARRANGEMENT FOR DRIVING A ROTARY TOOL. These applications are assigned to the assignee of the present application. Such a machine is operated so rapidly that a tool becomes worn out in a very short period of time from having drilled a very large number of holes. Frequent replacement of drills is required as the drills wear out. Also, drills of different sizes must be provided for the machine to form the variety of holes required in the production of printed circuit boards. With a conventional tool changer so much time will elapse in removing and inserting drills that production is slowed down and expense therefore becomes greater. Also, the conventional tool changer can accommodate only a relatively small number of tools. An operator must be continually restocking the tool changer which is a laborious and time consuming operation. This also increases the chance for error in providing some tool of the wrong size in the tool changer magazine.
Conventional tool changers also tend to be overly complex and expensive to construct and maintain.